--- llvm-3.4.ebuild	2014-03-02 18:02:16.000000000 +0100
+++ llvm-3.4.ebuild1	2014-03-02 18:02:16.000000000 +0100
@@ -171,6 +171,10 @@
 		epatch "${FILESDIR}"/clang-3.4-gentoo-install.patch
 	fi
 
+	if [[ ${CHOST} == *-darwin* ]] ; then
+		epatch "${FILESDIR}"/llvm-3.4-fix_darwin_build.patch
+	fi
+
 	local sub_files=(
 		Makefile.config.in
 		Makefile.rules
@@ -210,6 +214,11 @@
 		$(use_enable libffi)
 	)
 
+	# Setup the search path to include the Prefix includes
+	if use prefix ; then
+		conf_flags+=( --with-c-include-dirs=${EPREFIX}/usr/include:/usr/include )
+	fi
+
 	if use clang; then
 		conf_flags+=( --with-clang-resource-dir=../lib/clang/${PV} )
 	fi
@@ -462,6 +471,10 @@
 				"${f}"
 			eend $?
 		done
+		for f in "${ED}"/usr/lib/clang/${libpv}/lib/darwin/libclang_rt.asan_{iossim,osx}_dynamic.dylib ; do
+			odylib="${f#$ED/}"
+			install_name_tool -id "${EPREFIX}/${odylib}" "${f}"
+		done
 	fi
 }